Broad long term objectives are to determine the pathogenic mechanisms involved in Mallory body formation. The specific aims are to 1) To determine the conformational changes in the cytokeratins during drug refeeding, [ethanol feeding and okadaic acid treatment during MB formation in the drug primed model of MB formation.] 2) To determine if hyperphosphorylation of cytokeratin filaments during drug refeeding, alcohol feeding and okadaic acid treatment is involved in MB formation in the drug primed mouse model. 3) To determine if heat shock protein [chaperone protein refolding] plays a role in preventing MB formation causing refolding of misfolded cytokeratin proteins. 4) To determine the role of the ubiquitin pathway of proteasome proteolysis of cytokeratins during MB formation. The approach will be to study the drug primed mouse model of Mallory body formation to determine the sequence of events postulated to be involved in the so called "empty cells" which are known to be capable of forming MBs. Since MB formation is a common and importan6t mechanism of liver cell injury in many types of liver disease including alcoholic liver disease, this new insight into the mechanisms involved in MB formation should make it possible to design treatment strategies to prevent and treat liver diseases where MBs are found. In summary: The study proposed will add important new understanding of the intracytoplasmic dynamics of cytokeratin protein synthesis, folding, polymerization, depolymerization and degradation as well as explain how cytokeratin aggregates accumulate in the cell, i.e. MB formation, when the balance between phosphorylation and dephosphorylation regulation is tipped in the direction of hyperphosphorylation.